36b00fae56bc9de09200fd4fe5cfd07ddb4352d8
braney
  Wed Sep 16 12:40:10 2026 -0700
hprcPclai: back to dense, with denseClick on, refs #35415, refs #38364

This track was moved to squish a week ago and pinned there with
onlyVisibility, for one reason: dense drew one merged row per subtrack
and emitted no per-item map boxes at all, so there was no hgc link, no
mouseOver, and no way to reach the ancestry scatterplot on the details
page.

denseClick removes that reason.  With it, every item on a dense row gets
its own map box, so it carries an hgc link and its own mouseOver while
still being drawn on the single dense row.  Measured on a build of this
branch at chr2:60,000,000-80,000,000, the seven default-on haplotypes:

dense, denseClick off      0 hgc links
dense, denseClick on    1249 hgc links
squish                  1235 hgc links

The rendered image does not change; only the image map does.

So dense is now the better mode for this data as well as the clickable
one.  Dense is always exactly one row per haplotype, where squish spreads
to three or four at whole-chromosome zoom and gets noisy.  onlyVisibility
moves to dense rather than going away: its real job is keeping a reader
out of pack, which at 463 subtracks would be enormous.

denseClick is inherited, so the single line on the composite covers every
subtrack, and hgTracks ignores a setting it does not understand, so the
line is inert rather than harmful on an older browser.

The same change goes into the GenArk contrib collection stanza.  Worth
knowing about the timing there: hprc2annot is listed in betaGenArk.txt,
and hgwbeta runs the release branch, so that copy will show a dense row
with no clickable items until the hgTracks change reaches beta.  The hg38
composite is alpha only and hgwdev CGIs are built from master, so it
picks the behavior up as soon as this lands.  Neither copy is in
publicGenArk.txt, so no RR user sees either state.

hprcPclai.ra is generated, so the change is in hprcPclaiMakeTrackDb.py and
the .ra was rebuilt from the same index CSV; the regenerated file differs
only in those three lines.

diff --git src/hg/makeDb/scripts/hprcPclai/hprcPclaiMakeTrackDb.py src/hg/makeDb/scripts/hprcPclai/hprcPclaiMakeTrackDb.py
index cdff2037ef4..076b59ca378 100755
--- src/hg/makeDb/scripts/hprcPclai/hprcPclaiMakeTrackDb.py
+++ src/hg/makeDb/scripts/hprcPclai/hprcPclaiMakeTrackDb.py
@@ -68,37 +68,42 @@
     hapVals = sorted({h for _s, h in haps})
 
     out = open(outFname, "w", encoding="utf-8")
     w = out.write
     w("# hg38 pcLAI local ancestry, one subtrack per HPRC Release 2 haplotype.\n")
     w("# Generated by hg/makeDb/scripts/hprcPclai/hprcPclaiMakeTrackDb.py -- do not\n")
     w("# hand-edit; see hg/makeDb/doc/hg38/hprcPclai.txt.\n\n")
 
     w("track %s\n" % TRACK)
     w("compositeTrack on\n")
     w("shortLabel pcLAI Ancestry\n")
     w("longLabel Point cloud local ancestry inference (pcLAI) along HPRC assembly haplotypes\n")
     w("group hprc\n")
     w("type bigBed 9 +\n")
     w("itemRgb on\n")
-    # squish, not dense, and pinned there. In tvDense hgTracks draws one merged row
-    # per subtrack and emits no per-item map boxes at all, so the scatterplot on the
-    # details page and the mouseOver below both become unreachable. squish keeps
-    # every map box, and since the windows tile without overlapping each haplotype
-    # still collapses to one or two thin rows instead of pack's ~50.
-    w("visibility squish\n")
-    w("onlyVisibility squish\n")
+    # dense, and pinned there. This track was on squish only because dense drew
+    # one merged row per subtrack with no per-item map boxes, which left the
+    # mouseOver below and the details-page scatterplot unreachable. denseClick
+    # (#38364) gives a dense row one hgc link and one mouseOver per item, so
+    # dense now does everything squish did and always takes exactly one row per
+    # haplotype, where squish spreads to three or four at whole-chromosome zoom.
+    # denseClick is inherited, so the one line covers all 463 subtracks.
+    # onlyVisibility stays, moved to dense: it is what keeps a reader out of
+    # pack, which at 463 subtracks would be enormous.
+    w("denseClick on\n")
+    w("visibility dense\n")
+    w("onlyVisibility dense\n")
     w("priority 30\n")
     # A whole chromosome holds a few thousand windows per haplotype, well over the
     # 1000-item default at which pack mode gives up drawing; the block structure
     # this track exists to show is only visible at that zoom.
     w("maxItems 40000\n")
     w("subGroup1 sample Sample %s\n" % " ".join("%s=%s" % (s, s) for s in samples))
     w("subGroup2 hap Haplotype %s\n" % " ".join("h%s=%s" % (h, h) for h in hapVals))
     w("sortOrder sample=+ hap=+\n")
     w("dimensions dimensionY=sample dimensionX=hap\n")
     w("dragAndDrop subTracks\n")
     w("dataVersion %s\n" % DATA_VERSION)
     w("\n")
 
     # Explicit priorities: without them the subtracks come out in an arbitrary
     # (in practice reversed) order in the image, and with several hundred rows a